NEW YORK — Lockheed Martin is best known as the $45 billion-a-year builder of the F-35 Joint Strike Fighter and other such war machines.

But as the wars draw down and defense money tightens, company CEO Marillyn Hewson has her sights set on everything from cybersecurity to alternative energy, hedging the company’s bets against the politics of austerity and the uncertainty of the congressional budgeting process.

“We’ve moved into cyber capability, to energy, clean energy capabilities, and we’ll see more of that,” Hewson said in a wide-ranging interview here recently. “We’re engaged in hypersonics. We’re engaged in advanced manufacturing, advanced materials like 3-D printing or digital-manufacturing-type things. We’re engaged in just a range of things that I think will help transform our business as we move forward as those areas grow.”

Still, there’s reason to be skeptical that a company with 115,000 employees that makes 61 percent of its sales with the Pentagon can really diversify around the edges enough to truly transform itself in a post-war era in which every defense contractor is competing for a piece of a smaller pie.

“Things are going to get a lot tougher going forward, and her job’s going to get a lot more difficult,” said Bill Loomis, an analyst for Stifel Nicolaus who tracks Lockheed’s financial performance, “particularly if Congress doesn’t stop sequestration, which starts again in fiscal 2016. That $115 billion gap in fiscal 2016 and beyond that’s supporting current programs is going to have to come out of somewhere, including a lot of Lockheed programs like Littoral Combat Ship, F-35.”

Hewson, the first woman to head the defense juggernaut, acknowledges that she’ll have to balance the company’s brand as the world’s largest defense contractor with declining resources.

“We’ve been at war for 12-plus years, two different wars, and we’ve had all these challenges, and we’ve just worn stuff out,” she said. “We’ve continued to fly aircraft and [drive] trucks and other things that are really just worn out and need to be replaced, so that is a very big challenge for our customer.”

Hewson’s appointment at the end of 2012 came as a surprise when Chief Operating Officer Christopher Kubasik resigned for having a relationship with a subordinate — and she spent the first year of her tenure proving she deserved the job.

A 61 percent jump in Lockheed’s stock last year helped Hewson earn the trust of her investors and a realignment of the top F-35 executives went a long way toward fixing the communication woes that have plagued the fighter program. The company has “right-sized” in the past few years, cutting executive jobs and downsizing factories and managing to turn out successful financials even when faced with sequestration.

But Lockheed, which attributed 82 percent of its $45 billion net sales in 2013 to the government, can’t dodge the downturn forever.

As the war business declines, Lockheed’s already begun to look for business outside its current portfolio. The company acquired the Scotland-based transportation IT company Amor Group last September, and bought the German air traffic management company BEONTRA and the Massachusetts cybersecurity firm Industrial Defender in March.

Loomis said he expects the company to continue to look at smaller acquisitions in the $100 million to $300 million range. And Hewson has expressed willingness to make even some higher-risk acquisitions in the $1 billion range.

Now, more than 15 months into her gig and three months after taking the reins from her predecessor, Bob Stevens, as chairman of Lockheed’s board of directors, Hewson — a team player who’s packed up and moved eight times in her 31 years with the company — is looking forward.

“Any business needs to be staying abreast of their external environment and the markets that they operate in,” she said.

Norm Augustine, a former Lockheed chief executive who oversaw the Lockheed and Martin Marietta merger in 1995, says he sees parallels between the budget situation Hewson is facing now and his tenure during the downturn in the 1990s that led to Lockheed’s consolidation.

That’s not to say that another large-firm merger is likely, but Augustine said it’s clear that as defense spending declines, there’s an understanding in the industry that executives need to think differently than they have in booming budget times to be successful.

“There are opportunities in a declining market,” he said. “It was only in hard times when people sat down and said, ‘What’s our future?’ and made the really tough decisions that we’ll sell the company or buy a company or what have you. I think there’s opportunity there, but it won’t be easy.”

Lockheed also faces the added challenge of being at the head of the defense industry pack, Augustine said.

“The most dangerous place to be is in first place,” he said, “because, one, you’re complacent that what got you there is going to keep working and keep you there and of course that’s not true. And the other is that you’re everybody else’s target.”

The former CEO of one of Lockheed’s competitors, BAE Systems’ Linda Hudson, said their paths often crossed before she retired in January, particularly on panels and in discussions about women in leadership.

“While on a day-to-day basis she has a reputation for being very, very competent and effective, her demeanor to the outside world comes across as very confident, very calm and very capable,” Hudson said. “I think that style, by the way, will go a long way in dealing with the difficult issues that over time have arisen on programs like the F-35.”

The F-35 Lightning II program has caused Lockheed no shortage of grief. But many industry watchers credit Hewson for improving the troubled Lockheed-Pentagon relationship, in part because of her appointments of Orlando Carvalho to head the company’s aeronautics division and Lorraine Martin to handle the F-35 program.

The previous executive vice president of aeronautics, Larry Lawson, retired just three months into Hewson’s tenure, after the head of the Pentagon’s F-35 program, Air Force Lt. Gen. Christopher Bogdan, accused Lockheed Martin and engine-maker Pratt & Whitney of “trying to squeeze every nickel out of that last F-35 and that last engine.”

“One of the things she said when she first took over was that she wanted to improve the communication between the contractor and the government on the F-35 program,” said Michael Lewis, an industry analyst with the Silverline Group. “She’s got tailwinds on that program now rather than headwinds in a lot of negative sentiment on that program. So that’s No. 1 on the tasks accomplished list. You can check that box.”

Rep. Chris Van Hollen, a Democrat whose Maryland district includes Lockheed Martin’s headquarters, said he’s spoken with Hewson about the F-35 program, and she’s clearly made it a priority to deliver the aircraft on time and on budget, as well as be more receptive to input from the Pentagon.

“She’s worked to address those concerns,” Van Hollen said. “It’s important that Congress continue to hold all the parties accountable to make sure that we get the best value for the taxpayer, and she understands that.”

Though the F-35 is a crucial part of Lockheed’s portfolio, other recent acquisitions show that Hewson is not afraid of taking the company in a new direction, Hudson said.

“She’s making some interesting acquisitions and trying to position herself for what she sees going forward,” Hudson said. “I’m not privilege to Lockheed Martin’s strategy, but in times like these when the industry is in a downturn, it’s really an opportunity to make a move.”

So far, the acquisitions have been more symbolic than substantive, said industry analyst Loren Thompson of the Lexington Institute, but bigger bets could be on the horizon.

“If her bets outside defense prevail, the character of this company could be far different a dozen years from now than it is today,” Thompson said. “What they do is create a sense of hope about the future regardless of where Pentagon demand is headed.”

Augustine agreed that the acquisitions are a hint of what’s to come for Lockheed.

“When your primary market is declining, you have three choices: One is to decline. One is to build market share. And one is to look for new markets,” he said. “Presumably, they don’t want to decline. And they already have a fairly large market share; they’re not likely to double it. And so one alternative is to look elsewhere for markets. That is really hard but not impossible.”

And while Lockheed has had a successful past, the future as of now depends on Hewson.

“I’m very proud of what they’ve accomplished over the years; I think our nation’s military would not be as strong if it weren’t for them,” Augustine said. “On the other hand, what happened yesterday doesn’t count.”